The invention relates to a process for the preparation of 1,2-disulfone compounds.
1,2-Disulfone compounds have diverse potential uses. It is known, for example, from Bull. Chem. Soc. Jap. 45, 2906 (1972) (CA 78:15196c) that diaryldisulfones are photoreactive and dissociate into radicals under the action of radiation. According to JP No. 58-83844 (CA 101: 63684a) such compounds are used as agents which produce free radicals in photosensitive compositions for photolithographic purposes. According to Makromol. Chem., Rapid Commun. 4, 539 (1983) (CA 99: 140979v) and JP No. 59-197422 (CA 102: 186029u), diaryldisulfones can be used as agents which crosslink by radiation for epoxy-functionalized acrylate polymers. 1,2-Disulfones are moreover useful reagents and synthesis intermediates, for example in the synthesis of pharmaceutically active compounds.
A preparation process for 1,2-disulfones having a wide range of substituents, with, in principle, any desired radical, and which is easy to carry out has not heretofore been known.
According to JP No. 58-83844, diaryldisulfones are accessible by reaction of alkali metal arylsulfinates with arylsulfonyl chlorides. This method is expensive, especially when used to obtain unsymmetrically substituted disulfones. The product yields which can be achieved are moreover unsatisfactory.
A synthesis route which is simple in principle is described in Z. Naturforsch. 21b, 813 (1966). In this article, symmetrical phenyl, p-tolyl and naphthyl disulfones were prepared by oxidation of the corresponding disulfonyl hydrazines, and yields of between about 30 and 50% were achievable. Only mercury oxide and N-bromosuccinimide were used as oxidizing agents. The choice of these oxidizing agents, which are unusual because they are expensive, and, in the case of mercury oxide also problematical, and all in all are to be described as "exotic", suggests that customary oxidizing agents were not successful in this reaction.